Means for preventing the backward propagation of flame.



. A. 0. IONIDES, JR. MEANS FOR PREVENTING THE BAGKWARD PROPAGATION OF FLAME.

' APPLICATION FILED 001. 4, 1912.

1,061,847. Patented May 13, 1913.

m In

a a I W/ Ill/422291 114!!! 1 xmwmsmf ,INVENTOR ATTORNEY %\'ITN 'iSES ing 25 layer, p p offers considerable resistance to the how ot "UNIT To all whom 2'1- w tay concern Great Britain and Ireland, and residing' at Means :for Preventing the Backvv'ar'diProp aloWing-is'a specification. This invention relatesto a'devicefor preventing the backward propagat on of" a flame along a conduit-"conveying a com bustible gas mixed'with a supporter. of combustion- I11 7 '1 Insuch devicesja'sh'a've alreadybeen"pro posed," th'ef fiame-is' spread into thin layer in can annular assage betwen'-"two cy1in-" drical surfaces forming a part of the conthe same section 1 area as t theduityand' of I latter. 1 In order that such a device shall be effective it has been-"found necessary to spread the flame into an exceedingly thin with the result that such a device 5; the gaseous mixture under normal icondi t1ons.; a

The obj ect of the present invention is" to overcome the above disadvantage. This *winvention' consists in a' devl'ce 1H fgmihich the backward propagation ofa flame along-la conduit is prevente'd by spreading" the flame radially ina p'assage of subs'ita ntially constant cross sectional area.

The invention also consists. in"a"d'ev ice which prevents the'backward propagation 0f azi'fiame' along a conduit by '-a"radial spreading of the flame, but oflers mini- 40 mumicresistance -to" the normal flow of gas in therconduit; a v a l-Thfeginvention further consists in the i'mproved; device for preventing the backward propagation of 51, flame along a 1 conduit as herefinatter described.

Referring now, to the accompanying idrawingseFigures 1, 2 and 3 show in sectional elevation three forms ofa device 'a? cor ingrtoithe presentinvention.

cording; towlthe construction shown inFig.

ombustio i conduit part of ED STATES I ,q tonnage. Be it known thatf -I, ALEXANDER Cons'ra v: TINE'IoN-nms, J r., a "subject of the K 1ng 'ot cation of Flame along a Conduit Convey- Combustible Mixture, t 5.

' terto one of larger perimeter.

however, to prevent the backward propagatlUIl'OfiL' flame alon'gthe conduit, that is in f "to alsu'dden chang Int-partying theinvention into effect Lac-' provided in the main conduit, a,

reat'er sectional area than the main PATE OFFICE.

nEn oonsrANrmE IONIDES, JRQOFLONDOIiT, ENGLAND.

s fofirnnvtqfihiri BKcKWAimrRoPAGATIoN or FLAME. a 1

L -f b cm ioiiom er r en Pate'ntedMa'y 13,1913, Application filed catcher-4; 1:912?"stiiivpr'zagt i theends of the enlarged endutlpaf s'ib; there a a g, form ingjaf chambeifioff considerably greater sectional area thane ,the main conduit or en- "largedpar't; \Vitliin saidy chamber. there is fixedia rj emb erggz; having a conical surfacing the direction of normal flow u; of" the gaseous mixture, which is in the direction indicatedby the arrows,

surface, f, at the other p "Thefcaslng' surface, ,"g adjacent tOtllQCOIll-l cal 'surfa'cem; is also'conical and of such di i ionsflit atb twen'the twd conical surg a ifaces'elandg, there an annular passage -Wh1ch',; il s lt diverges and consequently. III-l creases inperim'eter, 1s correspondingly de creased in width sothat the cross sectional "area o fthepassage remains practically constantQand 1s equal to thatoif the enlarged conduitpartb I {In .fl'owing through such a passage the gaseous mixture is gradually --spread intd'a layer'of decreasingthickness until the annular passage between the cylindrical surface of the 'member, d, and the -casi ng, c, is reached, which, passage is also of the same sectional area as the enlarged conduit part, b. In this Way them'inimum In der;

resistance is ofi'eredtothe' mixtureinfiowthe direction opposite tot-hat of the arrows,

- g direction of travel, 1s spread radiallyinto af thinj la'yer, the sectio'nal area "ofvvhichf always'fremains con- 7 stant and'tqua1?td; that of ftheconduitjpartfl.

For this-purpose, when theend surface,"

f of the member;

surface; h, of the casing a, must be hyper 'f.

bolicali ';-The curve of the surface h,vvill there 'foreibe'such'that the p roductofthe di t nge' of anypointbn the lsurface,fh,]meaSured from the axis,"k, 7c,-"of the conduitffi'nto the distance from such point to the'fiat surface,"

is' 'constant' and equal to hal f' 't'he square {of :the'radius of the enlarged conduit part",

b. Obviouslyfthe isame result'may be obtaihed by making the end surface, f, member, (1, hyperbolicah' While the surface, 72; of the surrounding casing is flat.

of the According tothe modified construction f the device shown in Fig. 2, the chamber within the casing, 0, in the conduit part. b, is cylindricahand has flat end walls, m. The inserted member, (Z, is now in the form of a 5 disk, and in order that the cross sectlonal area for the passage of gas throughout the enlarged conduit part, b, shall remain constant, the disk surfaces, n, are curved so as to maintain between these surfaces and the flat surfaces, m, a passage of constant cross sectional area in spite of its increasing perimeter, the disk surfaces being for this purpose substantially hyperbolical. Suitable distance pieces, 0, placed between the flat surfaces, m, and the disk, at, maintain the latter in its correct position relatively to the casing, 0. With such-a modified form of the device, a flame passing in either direction alongthe conduit will have its direction of travel suddenly altered and at the same time be spread radially into a thin layer while maintaining a constant cross sectional area as in the previously described form. In a device according to the present invention, the backward propagation of the flame is prevented by spreading the flame into a layer of such a thickness that cooling causes the flame to be extinguished. The amount of spreading to which the flame be thus subjected in order to effect this, depends upon the constituents and the proportion thereof in the combustible gaseous mixture. For a mixture of petrol vapor and air in the proportion giving complete combustion of the former, it has been found that back ward propagation of the flame is prevented if the latter be spread into a layer of about one-sixteenth of an inch in thickness, while if the mixture is a self-burning one of average coal gas and air the former will be extinguished if spread into a layer of about one-fiftieth of an inch in thickness.

Although the amount of spreading must bedeterminedfor diflerent mixtures, it may 4 be greatly reduced by slightly modifying the device in the manner illustrated in Fig. 3. In this modification the mixture under normal conditions flows in.the direction of the arrows shown, and on entering the easing, 0, by the conduit part, b, it passes into an annular passage, 79, formed between the casing wall, 0, and an inner wall, 9, concentric therewith. The passage, 79, is continued between the member a, and the other side of the concentric wall, 9, and thus corresponds to the passage between the casing, 0, and cylindrical member, (Z, in the device shown in Fig. 1. The mixture thereafter enters the spreading passage between the flat surfaces, m, and the hyperbolic surface, f, at the narrowest part of said passage, and thereafter passes radially with respect to the member, a, and outward to the conduit part, b. Opposite the latter is arranged a chamber, 7', the length of which is usually variable indicated by the arrows shall strike the end walls of the chamber, and thereby be completely reversed in their direction of travel.

In this way a considerable amountof the initial energy of the back fire is absorbed, andv consequently the further propagation of the flame is prevented by spreading the flame to a lesser degree than hitherto. This form of the de-' vice offers the advantage that the valve by which the flow of mixture is controlled can be placed in the outgoing conduit part, 30 b, and arranged with its spindle parallel to the axis thereof so that the wilve can be operated from the side of the device on which the chamber, 1, is situated.

It will be understood, of course, that in a s5 device such as shown in Figs. 1 and 2 the area of flow throughout the device may be made equal to that of the main conduit, a, instead of that of the enlarged conduit, 6, although the latter arrangement is preferable as the device then offers less resistance to the normal flow of the mixture along the conduit.

Many modifications, it will be seen, can be made in the manner of carrying the invention into effect without in any way departing from the spirit of the same.

claim- 1. A device for preventing the backward propagation of flame, comprising in c0mbination a conduit conveying combustible gaseous mixture, a part of said conduit of greater cross sectional area, annular surfaces connecting said enlarged part with the remaining part of the conduit, a cylindrical member inserted within the enlarged part, said member having an end surfacelco-acting with one of said annular surfaces to form a passage at right angles to the main conduit, the product of the width of which passage into the corresponding radial distance from the axis of the conduit is constantfor all such distances, whereby a backwardly propagated flame on entering said passage is spread in a plane substantially at right angles to the conduit, while maintaining a constant cross sectional area.

2. A device for preventing the backward propagation of flame, comprising in combination a conduit conveying combustible gas- 1 eous mixture, a part of said conduit of greater cross sectlonal area than the remaining part, annular surfaces connecting the enlarged part with .the remaining part of the conduit, a cylindrical member inserted within the enlarged part, said member having an end surface co-acting with one of said annular surfaces, one of the two co-acting surfaces being fiat and the other concave but hyperbolic radially, thereby forming a radial passage situated in a plane at right angles to the conduit, and of constant cross sectional area.

3. A device for preventing the backward propagation of flame, comprising in combination a conduit conveying combustible gaseous mixture, an enlarged part of said conduit of greater cross sectional areav than the remaining part, annular surfaces connecting said parts, a member inserted in said enlarged part, said member having a concave end surface co-acting with one of said annular surfaces which is flat, the concave surface being radially convex and hyperbolic so as to form between said c0acting surfaces a passage in which the flame is spread in a plane at right angles to the conduit, while its cross sectional area is maintained constant.

4. A device for preventing the backward propagation of flame, comprising in combination a conduit conveying combustible gaseous mixture, said conduit having a cylindrical part of increased cross-sectional area, a disk inserted within said part, and having a substantially hyperbolic surface which coacts with the flat surface of the cylindrical part to form a radially extending passage of substantially constant cross-sectional area.

5. A device for preventing the backward propagation of flame compri 'ng in combination a conduit conveying combustible gaseous mixture, an enlarged part of said conduit of greater cross sectional area than the remaining part, fiat annular surfaces connecting said parts, a disk inserted in said enlarged part, said disk having concave faces which radially are convex and hyperbolic whereby sai faces co-act with the flat annular surfaces to form passages-in which the flame is spread in a plane at right angles to the conduit while maintaining .a constant cross sectional area.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

ALEXANDER CONSTANTINE IONIDES, JR.

\Vitnesses O. J \VORTH, CARL R. Loor. 

